scientists found cell use was not at a greater use for developing brain cancer. >> they didn't find a greater risk of tumors in the head or central system tumors. >> but london epidemiologist paul elliott says more research must be done on people who use the cell phone for decades. >> reporter: about 5 billion people worldwide, use a cell phone. and many say the convenience will always outweigh any potential health risks. >> you have a phone, you use it. and that's it. >> okay. >> hope for the best, right? >> i text more than i talk. so i'm not really worried about it. >> reporter: health experts say texting or finding other ways to keep your phone away from your head are always good ideas. >> use a hands-free device. because you will reduce exposure. >> reporter: danish scientists admit their study was somewhat limited because they examined personal accounts, not corporate ones. and business people usually spend more time on the phone. in london, tina kraus, wjz eyewitness news. >> some experts also recommend not keeping your cell phone in your pocket as a way to reduce your exposure